A folk song that was popular in my childhood describes a utopia of ineffective jails and crippled policemen. "In the Big Rock Candy Mountain the cops have wooden legs" --"The Big Rock Candy Mountain" (attributed to Harry McClintock, popularized by Burl Ives) The notion that we are better off with impaired police is widespread, particularly with regard to surveillance and databases. The recent revelation that the Defense Department has a project headed by John Poindexter to create a surveillance database called the "Total Information Awareness System" provoked a hostile response from William Safire and the Washington Post editorial page, among...

Astronomy Picture of the Day Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2003 January 6 Shadow Cone of a Total Solar Eclipse Credit & Copyright: Oliver Staiger (High Moon) Explanation: Sometimes, during a total eclipse of the Sun, a strange shadow of darkness can be seen stretching off into the distance. Called a shadow cone, they are visible because the Earth's atmosphere is not completely transparent, scattering sunlight and hence appearing blue during the day. Shadow cones are particularly dramatic...

Astronomy Picture of the Day Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2002 December 13 The Crown of the SunCredit & Copyright: (C2002) Wendy Carlos & Jonathan Kern (all rights reserved) Explanation: During a total solar eclipse, the Sun's extensive outer atmosphere or corona is an awesome and inspirational sight. Yet the subtle shades and shimmering features of the corona that engage the eye span a brightness range of over 10,000 to 1, making them notoriously difficult to capture in...

Astronomy Picture of the Day Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2002 December 9 Moon Shadow Moves Over Africa Credit and Copyright: EUMETSAT Explanation: When the Moon's shadow reached out and touched the Earth last week, the result was a solar eclipse. Such an eclipse is total only for observers located along a narrow path corresponding to the ground track of the shadow's dark central portion or umbra. For this eclipse, racing along at nearly 2000 kilometers per hour,...

Astronomy Picture of the Day Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2002 December 6 Zimbabwe Solar Eclipse Credit & Copyright: Murray Alexander Explanation: Normally hiding from view in the glare of the Sun, the shy solar corona came out to play Wednesday as a total solar eclipse graced morning skies over southern Africa. This telescopic image of the Sun's corona or outer atmosphere shimmering around the silhouetted Moon was recorded near the centreline of the total eclipse path, 10...

Astronomy Picture of the Day Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2002 December 3 Eclipse Over Acacia Credit & Copyright: Fred Espenak Explanation: On December 4th, for the second time in as many years, the Moon's shadow will track across southern Africa bringing a total solar eclipse to African skies. Reaching Africa just before 6:00 Universal Time, the narrow path of totality - corresponding to the path of the Moon's umbra or dark central shadow - will run eastward...